Esophageal adenocarcinoma (EAC) rates have increased 500% over the last three decades resulting in EAC being identified as the fastest increasing of all cancer types in the US. Esophageal cancer is an extremely deadly malignancy with 5-year survival rates consistently under 20%. The precise reasons for increasing rates of EAC are an active area of investigation. Persistent, symptomatic, reflux of gastric and duodenal contents, known as gastroesophageal disease (GERD), strongly correlate with EAC development and it's only known precursor lesion Barrett's esophagus (BE) via stimulation of cellular proliferation and apoptosis resistance. Other EAC risk factors include obesity, animal-based diets and to a lesser extent tobacco and alcohol use. Plant-based diets have generally been associated with a reduction of risk for EAC. Thus, the long-term goal of this research project is to develop efficacious strategies for the prevention of esophageal adenocarcinoma using a standardized proanthocyanidin rich cranberry extract (C-PAC). This preclinical research proposal stems from our published and preliminary unpublished results demonstrating that C-PAC decreases EAC cell viability by inducing cell death via apoptosis, autophagy and necrosis when apoptotic and autophagy machinery is defective. C-PAC treatment also induces an S-phase delay, causes G2-M cell cycle arrest, and significantly inhibits the growth of OE19 EAC xenografts in nude mice. Despite promising results supporting the chemopreventive application of C-PAC, substantial knowledge gaps remain with regard to the mechanisms of C-PAC-induced cell death. Studies proposed in this application will inform the signaling mechanisms involved in C-PACs cell death-inducing capacity, determine the in vivo efficacy of C-PAC for the prevention of esophageal adenocarcinoma utilizing a clinically relevant reflux-induced rodent model of EAC and test a novel imaging modality. Aim 1 will utilize a panel of authenticated esophageal cell lines that differ based on pathology, tumor suppressor gene status and acid sensitivity to dissect signaling pathways associated with C- PACs cancer inhibitory potential; the normal esophageal cell line (HET1A), Barrett's premalignant lines (CP- A,CP-B,CP-C,CP-D) and esophageal adenocarcinoma lines (FLO-1,JHEso-AD1,OE19,OE33) will be used to access cancer inhibitory mechanisms associated with C-PAC treatment. Aim 2 will focus on assessing the chemopreventive potential of C-PAC against EAC in the rat esophagogastroduodenal anastomosis (EGDA) model and improve our mechanistic understanding of C-PACs in vivo potential. Aim 3 will evaluate the use of a novel imaging technology, parallel frequency-domain optical coherence tomography (FDOCT), to detect early changes in nuclear morphology or sub-cellular structures linked with the development of preneoplasia, biomarker modulation and potentially to detect early chemopreventive efficacy. Positive outcomes of the proposed research will lay the foundation to rapidly translate these preclinical findings to clinical interventions in cohorts at increased risk for EAC, including BE patients or patients with esophageal dysplasia.